Polyphase tectonothermal history recorded in granulitized gneisses from the north Qaidam HP/UHP metamorphic terrane, western China Evidence from zircon U-Pb geochronology | |
Zhang, J (Zhang, Jianxin); Mattinson, CG (Mattinson, Christopher G.); Meng, F (Meng, Fancong); Wan, Y (Wan, Yusheng); Tung, K (Tung, Kuoan) | |
刊名 | GEOLOGICAL SOCIETY OF AMERICA BULLETIN |
2008 | |
卷号 | 120期号:5-6页码:732-749 |
关键词 | polyphase tectonothermal event gneiss north Qaidam Mountains U-Pb geochronology |
ISSN号 | 0016-7606 |
英文摘要 | High-grade gneisses of the north Qaidam high-pressure/ultrahigh-pressure metamorphic terrane enclose minor eclogites and ultramafic rocks. In combination with petrological data, sensitive high-resolution ion microprobe U-Pb geochronology on the granulitized gneisses in the Luliangshan and Xitieshan, western north Qaidam Mountains, reveals a polyphase tectonothermal history including Early Neoproterozoic and Early Paleozoic events. The rocks investigated are two granulite-facies paragneisses and one orthogneiss that both surround garnet peridotite in the Luliangshan, and two paragneisses that enclose eclogite in the Xitieshan. The inherited zircon cores from paragneiss and orthogneiss yield ages between ca. 1000 Ma and ca. 2500 Ma, representing Mesoproterozoic to Archaean source material for these gneisses. A ca. 900 Ma age obtained from one orthogneiss and one paragneiss is interpreted as the age of simultaneous Early Neoproterozoic magmatism and metamorphism. This Early Neoproterozoic tectonothermal event is similar in age to the Jinning orogeny, which is commonly recognized in the metamorphic basement of the south China block, and suggests that the north Qaidam Mountains have an affinity to the south China block. Early Paleozoic metamorphism is recorded in all gneiss samples. In conjunction with cathodoluminescence imagery and mineral inclusions, U-Pb dating of zircons reveals two Early Paleozoic age groups ca. 450 Ma represents the age of high-pressure granulite metamorphism (Grt + Rt inclusions in zircon; kyanite porphyroblasts), whereas ca. 425 Ma reflects the time of medium-pressure, granulite-facies metamorphism (Pl + Sil inclusions in zircon) and associated anatexis during decompression. The ages obtained suggest that the granulite-facies metamorphism lasted for similar to 25 m.y. and was related to the Early Paleozoic continental collision between the Qilian and Qaidam blocks, and to subsequent thermal relaxation and exhumation. |
学科主题 | 地质年代学 |
WOS关键词 | ULTRAHIGH-PRESSURE METAMORPHISM ; SOLID-STATE RECRYSTALLIZATION ; NORTHEASTERN TIBETAN PLATEAU ; ZONE SOUTHERN ALPS ; NW CHINA ; CONTINENTAL COLLISION ; FACIES METAMORPHISM ; GARNET PERIDOTITE ; BEARING ZIRCONS ; BOHEMIAN MASSIF |
WOS研究方向 | Geology |
语种 | 英语 |
出版者 | GEOLOGICAL SOC AMER, INC |
WOS记录号 | WOS:000255850400014 |
内容类型 | 期刊论文 |
源URL | [http://119.78.100.197/handle/2HKVOGP0/38710] |
专题 | 中国地质调查局 |
作者单位 | Beijing SHRIMP Ctr, Beijing 100037, Peoples R China |
推荐引用方式 GB/T 7714 | Zhang, J ,Mattinson, CG ,Meng, F ,et al. Polyphase tectonothermal history recorded in granulitized gneisses from the north Qaidam HP/UHP metamorphic terrane, western China Evidence from zircon U-Pb geochronology[J]. GEOLOGICAL SOCIETY OF AMERICA BULLETIN,2008,120(5-6):732-749. |
APA | Zhang, J ,Mattinson, CG ,Meng, F ,Wan, Y ,&Tung, K .(2008).Polyphase tectonothermal history recorded in granulitized gneisses from the north Qaidam HP/UHP metamorphic terrane, western China Evidence from zircon U-Pb geochronology.GEOLOGICAL SOCIETY OF AMERICA BULLETIN,120(5-6),732-749. |
MLA | Zhang, J ,et al."Polyphase tectonothermal history recorded in granulitized gneisses from the north Qaidam HP/UHP metamorphic terrane, western China Evidence from zircon U-Pb geochronology".GEOLOGICAL SOCIETY OF AMERICA BULLETIN 120.5-6(2008):732-749. |
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